Location: Commodity Utilization ResearchTitle: Structure-reactivity relationships between the fluorescent chromophores and antioxidant activity of grain and sweet sorghum seeds
Submitted to: Journal of Food Science and Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/25/2016
Publication Date: 2/16/2016
Citation: Uchimiya, M., Ni, X., Wang, M.L. 2016. Structure-reactivity relationships between the fluorescent chromophores and antioxidant activity of grain and sweet sorghum seeds. Journal of Food Science and Nutrition. 4(6)811-817.
Interpretive Summary: Cheap, easy, and rapid methods are on demand to characterize sorghum within the forage, food, and bioenergy sectors. This work developed such methods utilizing simple colorimetric and fluorescence techniques adaptable by the end-users including the breeders and factory personnel. Developed methods will provide a benchmark for the chemical characteristics underlying the phenotype.
Technical Abstract: Polyphenolic structures, such as tannins, are the putative cause of a variety of seed functions including bird/insect resistance and antioxidant activity. Structure-reactivity relationships are necessary to understand the influence of polyphenolic chromophore structures on the tannin content and free radical quenching ability determined by the traditional calorimetric methods. This study investigated the relationships between the structural attributes of fluorescent chromophore and the following seed characterization methods: procyanidin (by acid-butanol assay), flavonoid (by vanillin assay) contents, radical quenching (by DPPH assay), electron-donating capacity (by FeIII reduction), and 'max (by UV/Vis spectrophotometry). Distinctively different response was observed for the following seed categories: U.S. grain sorghum hybrids, African grain sorghum, and sweet sorghum. The U.S. grain sorghum was markedly unstable towards molding and the storage insects, and responded only to the DPPH assay. For sweet sorghum and African grain sorghum, linear correlation was observed between (i) the antioxidant activity (ii) the amounts of procyanidins and flavonoids, and (ii) and the aromaticity of fingerprint fluorescent structures.